I think that if one of them is suited for Skyteam it would be Alitalia. I don't see KLM/NW and Delta in the same alliance and besides I don't think it would make any sense. I think Alitalia operates a network different enough from current Skyteam members to be interesting. Besides I don't know why so many people try to place NW/KLM is a new global alliance. I think they are doing just fine with NW on their own (even though they'll probably have to expand at some point) and I don't really see any alliance they would fit in.

Northwest will get new planes and then work on expanding more although some is already underway (Italy service, more to Europe, and the huge MEM expansion)

Don't look to see NW/KLM try to get into a major alliance. They like what they have now and so do I. The service from these two airlines is much more personalized and consistent. NW/KLM basically market one product. NW/KLM has been and continues to be a major sucess in alliances. It is a global alliance as they fly to every continentant on the planet, just mostly at a smaller scale (for now).